DENVER — Former Colorado Gov. John Hickenlooper on Thursday ended his longshot bid for the Democratic presidential nomination and said he might run for the Senate in 2020 against a Republican considered one of the most politically vulnerable incumbents.

In a video message, Hickenlooper said many in his state had urged him to enter the Senate race. ``They remind me how much is at stake for our country. And our state. I intend to give that some serious thought,'' he said.

Colorado's shift to the left could put GOP Sen. Cory Gardner in jeopardy, and at least 10 Democrats have launched campaigns, setting up a competitive primary even before Hickenlooper, 67, decides.

Hickenlooper became a political giant in Colorado for his quirky, consensus-driven and unscripted approach to politics. He once jumped out of a plane to promote a ballot measure to increase state spending and he won two statewide elections during years of Republican waves. He also was Denver's mayor.

'Worthwhile' effort

He began his White House campaign in March, promising to unite the country. Instead, he quickly became a political punch line. ``While this campaign didn't have the outcome we were hoping for, every moment has been worthwhile,'' he tweeted on Thursday.

Founding a series of brewpubs made Hickenlooper a multimillionaire. But shortly before taking his first trip to Iowa as a presidential candidate, he balked on national television at calling himself a capitalist. Then, at a CNN town hall, he recounted how he once took his mother to see a pornographic movie.

With the campaign struggling to raise money, his staff urged Hickenlooper to instead challenge Gardner. But Hickenlooper stayed in and hired another group of aides in a last-ditch effort to turn around his campaign.

He positioned himself as a common-sense candidate who couldn't be labeled a ``socialist'' by Republicans. But Hickenlooper couldn't make his voice heard in the crowded Democratic field of about two dozen candidates.

Not much of a speaker

It didn't help that, by Hickenlooper's own admission, he was a mediocre debater and an erratic public speaker. In the end, he could not scrape together enough money for many of his trademark quirky ads, only launching one in which avid beer drinkers toast Hickenlooper by comparing him to favorite brews.

Hickenlooper softened his denials of interest in the Senate in recent weeks as his campaign finances dwindled and pressure increased from other Democrats. He started telling people he'd decide by the end of this week.

He even met with Colorado's Democratic secretary of state, Jena Griswold, who was mulling a run against Gardner. Griswold last week announced she would not challenge Gardner, and that helped to spark speculation among Colorado Democrats that Hickenlooper would eventually jump in.

If he entered the Democratic primary, Hickenlooper would be ``the absolute favorite,'' said Mike Stratton, a veteran Democratic strategist in Denver.

But some of Gardner's challengers have said they don't intend to step aside even if the former governor runs.

``What I heard Gov. Hickenlooper tell everybody who asked is he wasn't cut out to be a senator and didn't want the job,'' former Colorado House Speaker Andrew Romanoff, one of the primary contenders, said in a radio interview.

Hickenlooper isn't the first Democratic hopeful to end his 2020 presidential bid. U.S. Rep. Eric Swalwell of California announced his departure in July.